(a) Field of the Invention
The present invention relates to a device for the gasification and flow control of liquefied petroleum gas (hereinafter referred to as "LPG") in an apparatus such as a gas lighter for cigars and cigarettes, a gas igniter and a portable gas torch, said apparatus comprising a pressure container, a valve and a nozzle, said pressure container containing LPG, said LPG being subjected to gasification and flow control when said valve is opened, gasified LPG being emitted through said nozzle.
(b) Description of the Prior Art
The following are conventional devices for the gasification and flow control of LPG in an apparatus comprising a pressure container, a valve and a nozzle, said pressure container containing LPG, said LPG being subjected to gasification and flow control when said valve is opened, gasified LPG being emitted through said nozzle.
(1) A device adapted to perform the gasification and flow control of LPG by means of a compressed porous elastic material. LPG is subjected to gasification and flow control when it passes through the compressed porous elastic material. PA0 (2) A device adapted to perform the gasification and flow control of LPG by means of a microporous film only, as disclosed by Japanese Patent Laid-Open Publication No. Sho 51-148576. This publication also shows an embodiment in which a space called gasification chamber is disposed at a downstream side of said microporous film.
The above-mentioned device (1) adapted to perform the gasification and flow control of LPG by means of a compressed porous elastic material has an advantage that it is possible to adjust the flow of LPG. However, in this device, the amount of emission of gasified LPG has a tendency to vary with the lapse of time because the property of said elastic material changes with the lapse of time. Therefore, it is necessary to determine the flame length at the time of manufacture on the basis of an expectation as to how the flame length will vary with the lapse of time. It is very difficult to do so.
The above-mentioned device (2) adapted to perform the gasification and flow control of LPG by means of a microporous film only has been developed with a view to obviating the aforesaid disadvantage of the device (1). However, when the device (2) is applied to an apparatus such as a gas lighter for cigars and cigarettes, a gas igniter and a portable gas torch, the effective penetration diameter of the microporous film (the diameter of a portion of the microporous film through which portion LPG can pass) is as small as about 2 to 5 mm. Since the effective penetration area of the microporous film (the area of a portion of the microporous film through which portion LPG can pass) is proportional to the square of the effective penetration diameter thereof, even slight variations of the effective penetration diameter of the microporous film change the flow of LPG very much. Therefore, in the above-mentioned device (2) adapted to perform the gasification and flow control of LPG by means of the microporous film only, the unevenness of the effective penetration diameter of the microporous film causes the amount of emission of gasified LPG to vary. Furthermore, in said device (2) adapted to perform the gasification and flow control of LPG by means of the microporous film only, the amount of emission of gasified LPG is directly influenced by the variations of vapor pressure within the pressure container which are caused by the changes of ambient temperature (external temperature). When the ambient temperature is low, the amount of emission of gasified LPG has a tendency to become too small. When the ambient temperature is high, the amount of emission of gasified LPG has a tendency to become too large. This may cause disadvantages or dangers of ignition miss or forming a too small or too large flame.
Said gasification chamber of the above-mentioned device (2) is a space disposed at a downstream side of said microporous film so as to obtain a fixed effective penetration area of the microporous film. In this embodiment, however, LPG is liable to be condensed into small drops of liquid which may gush out when the valve is opened.